Translation:My younger brother is thirsty, so he wants to drink water.
I know and understand that "要“ can mean want, but it also indicates necessity, so I feel that "...he needs to drink water" is also acceptable.
I agree, but the "to drink" is superfluous. "Thirsty" telegraphs "drink," not wash.
I think that 'He needs to drink water' is also an acceptable translation here. Based on the context one cannot assume that he wants to drink.
"my younger brother is very thirsty and he wants to drink water" was rejected but I think it's ok
subsequently "my younger brother is very thirsty so he wants to drink water" was also rejected, and is also fine
"My younger brother is thirsty, he wants to drink water" 也应该可以了. 你们的答案数据库请调整了. A lot of mistakes for you to fix!
There is no implication of causation in this sentence. It's just two clauses strung together by a comma.
I disagree. I think it is implied that he wants to drink water because he's thirsty, a natural conclusion to jump to.
Sometimes we're required to write "younger/older brother/sister" and sometimes we're not required to include the "younger/older." First this needs to be consistent. And secondly we should not have to write "older/younger" every time. English does not care about that distinction any more than it cares about the distinction between a singular and a plural "you."
要 means both want and need in certain contexts. He needs to drink water is also an acceptable answer.
The course's inconsistency in deciding whether "要" means want or need is really not acceptable, especially considering that either use makes sense in the context.
In order to contain "so" doesn't the Chinese sentence need 所以/suoyi?
"...he wants a drink of water" or "wants to drink some water" are more common phrases than "wants to drink water" which sounds almost childish to me.